This is a weekly series on the latest happiness research. Learn and be merry! 

Danish DNA – Research out of the University of Warwick found that the closer a nation’s DNA is to Denmark’s (the happiest country), the happier it is.

Don’t put off happiness – Research published in the Journal of Happiness Studies found that well-being and life satisfaction improved at retirement, dipped a few years later, and stabilized around age 70. In the end, retirement doesn’t make you much happier than before.

Sing along – Research by Spotify and the University of Groningen explored the relationship between songs and emotions, finding that “Birthday” by Katy Perry and “Best Day of My Life” by American Authors produce happiness.

Glass two-thirds full – Research by PsychTests found that people who are happiest, most satisfied with relationships, most resilient to stress, and subjectively healthiest aren’t extreme optimists. Instead, on a scale of 1-100, they rank around 63-68 on optimism.

Move to Louisiana – Research out of Harvard and the Vancouver School identified the happiest cities in America. The top five are all in Louisiana – Lafayette, Houma, Shreveport-Bossier City, Baton Rouge, and Alexandria – and New York City is the unhappiest. In general, growing and metropolitan areas tend to be unhappier.

Surprise me – A survey of 2,000 Brits by DoubleTree suggested that little surprises are what make us happiest. 82 percent of people said the best things in life are unexpected, and their top five happy moments included finding money you forgot about, the sun shining, getting an unexpected discount at the cash register, getting something for free, and climbing into bed with fresh sheets.

Control yourself, man! – Research in the Journal of Personality suggests that people with more self-control are happier.

Mixing business and pleasure – A LinkedIn study found that 46 percent of professionals believe work friendships are important to their happiness. This is particularly true of millennials, 67% of whom would share things like salary, relationships, and family issues with coworkers.

Photo by Flickr user col&tasha